Water can be absorbed by and contaminate hydrocarbon fuel. It may enter the fuel tank holding the hydrocarbon fuel by condensation, hydroscopic attraction, or some other means. Fuel tanks and fuel delivery systems that use fuel contaminated by water will have problems such as icing, rust, and algae growth. In addition, the water can damage fuel injector pumps, injection nozzles, and carburetors.
Ethanol blended hydrocarbon fuels are particularly difficult to dry because the desiccants used to absorb water also absorb ethanol. If an ethanol is removed from an ethanol blended fuel when water is removed, the fuel will not perform as expected.